wiki:Cnbp2019/Agenda/NetworkSetup

Version 11 (modified by admin, 6 years ago) ( diff )

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Campus Network Design - Network Setup

In this tutorial we will establish dual stack network connectivity within all nodes of the network given below.

IP Address Plan

Device Management IP Address MGT Network MGT VLAN
FAC1 10.XY.2.1 10.XY.2.0/24 VLAN 2
FAC1-BLD1-FL0 10.XY.2.2 Ignore(LAB only) 10.XY.2.0/24 VLAN 2
FAC1-BLD1-FL1 10.XY.2.3 Ignore(LAB only) 10.XY.2.0/24 VLAN 2
FAC1-BLD1-FL2 10.XY.2.4 10.XY.2.0/24 VLAN 2
FAC1-BLD2-FL0 10.XY.2.5 Ignore(LAB only) 10.XY.2.0/24 VLAN 2
FAC2 10.XY.3.1 10.XY.3.0/24 VLAN 3
FAC2-BLD1-FL1 10.XY.3.2 Ignore(LAB only) 10.XY.3.0/24 VLAN 3
FAC2-BLD2-FL1 10.XY.3.3 Ignore(LAB only) 10.XY.3.0/24 VLAN 3
FAC2-BLD2-FL3 10.XY.3.4 Ignore(LAB only) 10.XY.3.0/24 VLAN 3

FAC1 Type VLANS/IP Native VLAN
F0/0 Routed Link 10.XY.0.6
2401:DD00:20XY:2::FFFF 		-
F0/1 Routed Link 10.XY.0.1
2401:DD00:20XY:1::FFFE 		-
F1/0 Trunk 10, 20 2
F1/1 Trunk 20, 30 2
F1/15 Access 1 -

FAC2 Type VLANS/IP Native VLAN
F0/1 Routed Link 10.XY.0.5
2401:dd00:20XY:2::FFFE 		-
F1/0 Trunk 60, 70 3
F1/1 Trunk 70, 80 3

FAC1-BLD1-FL1 Type VLANS Native VLAN
e0 Access 10 -
e7 Trunk 10 2

FAC1-BLD1-FL2 Type VLANS Native VLAN
e0 Access 20 -
e6 Trunk 10 2
e7 Trunk 10, 20 2

FAC1-BLD2-FL0 Type VLANS Native VLAN
e0 Access 20 -
e1 Access 30 -
e7 Trunk 20, 30 2

FAC2-BLD1-FL1 Type VLANS Native VLAN
e0 Access 60 -
e1 Access 70 -
e7 Trunk 60, 70 3

FAC2-BLD2-FL1 Type VLANS Native VLAN
e0 Access 70 -
e6 Trunk 80 3
e7 Trunk 70, 80 3

FAC2-BLD2-FL3 Type VLANS Native VLAN
e0 Access 80 -
e7 Trunk 80 3

DMC Type
e0 Access
e1 Access
e7 Access

Host Devices IPv4 IPv6
PC-1 10.XY.10.1 2401:DD00:20XY:1110::1/64
PC-2 10.XY.20.1 2401:DD00:20XY:1120::1/64
PC-3 10.XY.20.2 2401:DD00:20XY:1120::2/64
PC-4 10.XY.30.1 2401:DD00:20XY:1230::1/64
PC-5 10.XY.60.1 2401:DD00:20XY:2160::1/64
PC-6 10.XY.70.1 2401:DD00:20XY:2270::1/64
PC-7 10.XY.70.2 2401:DD00:20XY:2270::2/64
PC-8 10.XY.80.1 2401:DD00:20XY:2280::1/64
Monitoring-Server 10.XY.5.LMN 2401:DD00:20XY:5::AAAA/64
Server 192.168.XY.PQR 2401:DD00:20XY:1::PQR/64
GUI-PC via DHCP

FAC1 IPv4 IPv6
VLAN02 10.XY.02.1 -
VLAN05 10.XY.05.254 2401:DD00:20XY:5::FFFF/64
VLAN10 10.XY.10.254 2401:DD00:20XY:1110::FFFF/64
VLAN20 10.XY.20.254 2401:DD00:20XY:1120::FFFF/64
VLAN30 10.XY.30.254 2401:DD00:20XY:1230::FFFF/64

FAC2 IPv4 IPv6
VLAN03 10.XY.03.1 -
VLAN60 10.XY.60.254 2401:DD00:20XY:2160::FFFF/64
VLAN70 10.XY.70.254 2401:DD00:20XY:2270::FFFF/64
VLAN80 10.XY.80.254 2401:DD00:20XY:2280::FFFF/64

Log in to the the devices

In GNS3 topology right click on each network device and select Console. It will open your device console screen on a putty.

Initial Configurations

Before configuring the devices for the network setup. Let's configure some initial settings in the Core Network Devices.

Press the Enter key to go to the user mode of the FAC1 switch. Prompt will look as follows. 

FAC1#

In this privileged mode, you can check the router configuration by the following command. The configuration you see will be the default configuration 

FAC1#show run

To add configurations you have to go configuration mode. Type config terminal. Note the prompt change. 

FAC1(config)#

note: If you get following error,

%Error opening tftp://255.255.255.255/AccessRt-confg (Timed out)

Give the following command in the config mode, no service config

You can now start making configurations.

  • The first thing you have to add is the hostname of the device. The hostname is the device's identification. In this Lab device name or the hostname is automatically configured based on the GUI edits we did previously. If you want to change it you may use 
    hostname <device name>
  • Then let's give a enable secret. Which is a password you set when you go to the privileged mode from the user mode? We will use the class password as the enable secret 
    enable secret <class password>
  • Add the DNS server 
    ip name-server 192.248.1.161

In your production environment you may use your internal DNS resolver if needed.

  • Next, you can add a banner to your device. This will display every time you log in to the device 
    banner motd @ Unauthorized Access is Prohibited! @
  • Add more security by encrypting passwords in your config file 
    service password-encryption
  • Then lets's configure the line console which are the console port settings
    • Go to line console config mode 
      line console 0
    • Enable login authentication. Make sure not to save or exit the router after this command without executing the next command. 
      login
    • Set the password 
      password <class password>
  • Finally let's enable ssh (version 2) in the device. Type exit to go back to previous mode (config mode) from line console config mode
    • Configure a domain name. Use instXY.learn.ac.lk for this lab where XY is your group id. 
      ip domain name instXY.learn.ac.lk
    • Create an ssh user with a password. In here we will use the username admin with the class password 
      username admin secret <class password>
    • Create a certificate which will use for encryption 
      crypto key generate rsa
    • Give the size of key as 768 (minimum size needed to activate ssh version 2)
    • Then Configure the line vty 
      line vty 0 4
login local
transport input ssh
  • Now save the configurations. you have to Go to privileged mode and give the following command 
    #copy running-config startup-config
  • Check the configuration by show run command.

Apply these settings in FAC2 and FAC1-BLD1-FL2 as well

Core Network Layer

Let's start Configuring the connectivity between the core network (FAC1 and Fac2). We will start with Fac1.

  • Remember, the core network runs on routed ports. Get the IP from the table
  • Link to Firewall 
    FAC1(config)# interface fastEthernet 0/1
FAC1(config-if)# description Link to Firewall
FAC1(config-if)# ip address 10.XY.0.1 255.255.255.252
FAC1(config-if)#ipv6 address 2401:dd00:20XY:1::fffe/128
FAC1(config-if)#no shutdown
FAC1(config-if)#exit
  • Link to FAC2 
    FAC1(config)# interface fastEthernet 0/0
FAC1(config-if)# description Link to FAC2
FAC1(config-if)# ip address 10.XY.0.6 255.255.255.252
FAC1(config-if)#ipv6 address 2401:dd00:20XY:2::ffff/128
FAC1(config-if)#no shutdown
FAC1(config-if)#exit
  • On switch FAC2 we have only one routed port. Get the IP from the table
  • Link to FAC1 
FAC2(config)# interface fastEthernet 0/1
FAC2(config-if)# description Link to FAC1
FAC2(config-if)# ip address 10.XY.0.5 255.255.255.252
FAC2(config-if)#ipv6 address 2401:dd00:20XY:2::fffe/128
FAC2(config-if)#no shutdown
FAC2(config-if)#exit
  • Next, we need to configure routing among Core devices. We will configure dynamic routing / OSPF to distribute routing.
    • On FAC1, Define OSPF process and Process ID. In this lab use process ID as 1 
      FAC1(config)#router ospf 1
    • Give the router ID 
      FAC1(config-router)#router-id 10.XY.2.1
    • You are announcing to the core network (10.XY.1.0/24) in area 2. Use this command for this 
      FAC1config-router)#network 10.XY.0.0 0.0.0.255 area 2
FAC1(config-router)#exit
    • Now you have enable OSPF on FAC1 Switch. Now lets add the default Route. 
      FAC1(config)# ip route 0.0.0.0 0.0.0.0 10.XY.0.1
  • Follow the same steps in FAC2 

FAC2(config)#router ospf 1
FAC2(config-router)#router-id 10.XY.3.1
FAC2(config-router)#network 10.XY.0.0 0.0.0.255 area 2
FAC2(config-router)#exit
FAC2(config)# ip route 0.0.0.0 0.0.0.0 10.0.0.6

Distribution Layer

  • Finally configure fast ethernet interfaces switchport modes. You can find then from the table
    • Fisrt make the interface a trunk port. This is for the FacACore link 
      CampusCore(config)#interface FastEthernet 1/0
CampusCore(config-if)#switchport mode trunk
    • Define the encapsulation 
      CampusCore(config-if)#switchport trunk encapsulation dot1q
    • Give the Description of the interface 
      CampusCore(config-if)#description Core link to FacACore
CampusCore(config-if)#exit
    • Follow the same procedure for FacBCore link 
      CampusCore(config)#interface FastEthernet 1/1
CampusCore(config-if)#switchport mode trunk
CampusCore(config-if)#switchport trunk encapsulation dot1q 
CampusCore(config-if)#description Core link to FacBCore
CampusCore(config-if)#exit
  • You have successfully configured the CampusCore device for you core networks connectivity. Let's move on to FacACore device. 
    FacACore(config)# vlan 2
FacACore(config-vlan)# name Core
FacACore(config-vlan)# exit
FacACore(config)#interface vlan 2
FacACore(config-if)# ip address 10.0.2.2 255.255.255.0 
FacACore(config-if)# exit
FacACore(config)#interface FastEthernet 1/15
FacACore(config-if)#switchport mode trunk
FacACore(config-if)#switchport trunk encapsulation dot1q 
FacACore(config-if)#description Core link to CampusCore
FacACore(config-if)#exit
  • Now let's configure FacBCore 
    FacBCore(config)# vlan 2
FacBCore(config-vlan)# name Core
FacBCore(config-vlan)# exit
FacBCore(config)#interface vlan 2
FacBCore(config-if)# ip address 10.0.2.3 255.255.255.0 
FacBCore(config-if)# exit
FacBCore(config)#interface FastEthernet 1/15
FacBCore(config-if)#switchport mode trunk
FacBCore(config-if)#switchport trunk encapsulation dot1q 
FacBCore(config-if)#description Core link to CampusCore
FacBCore(config-if)#exit
  • Finally Verify the connectivity
    • Go to FacACore device
    • Go to privileged mode and ping CampusCore and FacBCore 
      ping 10.0.2.1
ping 10.0.2.3
    • You should get a positive reply with "!!"

Distribution Network Layer

Let's Start Configuring the distribution layer of your campus LAN. Here you will have to configure both Layer 3 switches (FacACore and FacBCore) and Layer 2 Switches (Dept1PC and Dept2PC). Let's start from Layer 3 devices.

  • Login to FacACore device
  • Go to config mode from privileged mode
  • FacACore is the Core device in Faculty A and It can have different departments. In this scenario department 1 is in faculty A and It's VLAN is VLAN10. Create VLAN 10 and Name it Dept1 
    FacACore(config)# vlan 10
FacACore(config-vlan)# name Dept1
FacACore(config-vlan)# exit
  • Then assign the IP Address to the VLAN interface. Get the IP from the table 
    FacACore(config)#interface vlan 10
FacACore(config-if)# ip address 10.0.10.254 255.255.255.0 
FacACore(config-if)# exit
  • Next configure fast ethernet interfaces switchport modes. You can find then from the table
    • Fisrt make the interface a trunk port. 
      FacACore(config)#interface FastEthernet 1/0
FacACore(config-if)#switchport mode trunk
    • Define the encapsulation 
      FacACore(config-if)#switchport trunk encapsulation dot1q
    • Give the Description of the interface 
      FacACore(config-if)#description link to Dept1Sw
FacACore(config-if)#exit
  • Follow the same procedure for FacBCore device. VLAN 20 name is dept 2. 
    FacBCore(config)# vlan 20
FacBCore(config-vlan)# name Dept2
FacBCore(config-vlan)# exit
FacBCore(config)#interface vlan 20
FacBCore(config-if)# ip address 10.0.20.254 255.255.255.0 
FacBCore(config-if)# exit
FacBCore(config)#interface FastEthernet 1/0
FacBCore(config-if)#switchport mode trunk
FacBCore(config-if)#switchport trunk encapsulation dot1q 
FacBCore(config-if)#description link to Dept2Sw
FacBCore(config-if)#exit
  • Now the Core devices are done, Let's Configure Layer 2 devices. Login to Dept1PC
  • Go to config mode
  • Create Vlan 10 and Give a Name 
    Dept1Sw(config)# vlan 10
Dept1Sw(config-vlan)# name Dept1
Dept1Sw(config-vlan)# exit
  • Next configure fast ethernet interface which connects to the Core device and give a description 
    Dept1Sw(config)#interface FastEthernet 1/15
Dept1Sw(config-if)#switchport mode trunk
Dept1Sw(config-if)#switchport trunk encapsulation dot1q 
Dept1Sw(config-if)#description link to FacACore
Dept1Sw(config-if)#exit
  • Configure fast ethernet interface, which connects to the User PC to an access port of VLAN 10 and give a description 
    Dept1Sw(config)#interface FastEthernet 1/0
Dept1Sw(config-if)#switchport mode access
Dept1Sw(config-if)#switchport access vlan 10
Dept1Sw(config-if)#description link to Dept1PC
Dept1Sw(config-if)#exit
  • Follow the same steps for Dept2Sw 
    Dept2Sw(config)# vlan 20
Dept2Sw(config-vlan)# name Dept2
Dept2Sw(config-vlan)# exit
Dept2Sw(config)#interface FastEthernet 1/15
Dept2Sw(config-if)#switchport mode trunk
Dept2Sw(config-if)#switchport trunk encapsulation dot1q 
Dept2Sw(config-if)#description link to FacBCore
Dept2Sw(config-if)#exit
Dept2Sw(config)#interface FastEthernet 1/0
Dept2Sw(config-if)#switchport mode access
Dept2Sw(config-if)#switchport access vlan 20
Dept2Sw(config-if)#description link to Dept2PC
Dept2Sw(config-if)#exit
  • You have configured your distribution layer. Check and verify the connectivity
    • Go to Dept1PC and try ping the gateway (VLAN 10 Interface IP of FacACore) 
      ping 10.0.10.254
    • You should get a reply
    • Try the same in Dept2PC

Connecting LAN to the Router

Your Campus LAN is connecting to the outside through a border router. Your CampusCore switch connects to this border router. In this link router's fast ethernet interface IP connects with the Core switch's vlan interface IP. Let's start configuring this link starting from the CampusCore.

  • Login to CampusCore switch and switch to config mode
  • Create VLAN 255 and name it Public 
    CampusCore(config)# vlan 255
CampusCore(config-vlan)# name Public
CampusCore(config-vlan)# exit
  • Then assign the IP Address to the VLAN interface. Get the IP from the table. In the real situation this VLAN could be a public IP range which is assign to your Institute. In this Lab we are using a private IP block. 
    CampusCore(config)#interface vlan 255
CampusCore(config-if)# ip address 10.0.255.253 255.255.255.0 
CampusCore(config-if)# exit
  • Next configure fast ethernet interface which connects to the Core device and give a description.You can find then from the table 
    CampusCore(config)#interface FastEthernet 1/15
CampusCore(config-if)#switchport mode access
CampusCore(config-if)#switchport access vlan 255
CampusCore(config-if)#description link to Border Router
CampusCore(config-if)#speed 100
CampusCore(config-if)#duplex full
CampusCore(config-if)#exit

Note: In the real environment you might not need Duplex and Speed. It will be negotiate automatically

  • Now you have done CampusCore configuration. Let's start routers Configuration.
  • Login to BorderRt Router and switch to config mode
  • Router's IP allocation is as follows. You can get your Router's IP address from here
Interface Name IP Address
Fast Ethernet 0/0 10.0.255.254/24
Fast Ethernet 0/1 <Your Routers WAN IP>
  • Let's configure the LAN port (fa 0/0) 
    BorderRt(config)#interface fastEthernet 0/0
BorderRt(config-if)#ip address 10.0.255.254 255.255.255.0
BorderRt(config-if)#description LAN Port connects to CampusCore
BorderRt(config-if)#no shutdown
BorderRt(config-if)#speed 100
BorderRt(config-if)#duplex full
BorderRt(config-if)#exit
  • Configure the WAN port (fa 0/1) 
    BorderRt(config)#interface fastEthernet 0/1
BorderRt(config-if)#ip address x.x.x.x 255.255.255.0
BorderRt(config-if)#description WAN Port Bridged with CampusLAN host
BorderRt(config-if)#no shutdown
BorderRt(config-if)#exit
  • You have successfully finished connecting CampusCore to the BorderRt router. Let's verify the connectivity using the ping command.
  • Go to BorderRt and ping to CampusCore switch's VLAN 255 Interface IP 
    ping 10.0.255.253
  • Now Check the routers connectivity in WAN port. Ping to the WAN Gateway 
    ping 192.248.6.254
  • Both these ping commands should give you a reply

Routing

If You go to the Dept1PC and try a Ping to Dept2PC (10.0.20.1) and BorderRt router LAN port(10.0.255.254), you will not get a reply. That is because you don't have inter VLAN routing yet. In this Lab we will enable OSPF in all the Layer 3 devices and we will add default routes as following table.

  • Following are the default routes of the devices
Device Default Route Destination IP Default Route Destination Description
BorderRt 192.248.6.254 This is Configured in the router in the Lab
CampusCore 10.0.255.254 BorderRt routers LAN interface IP
FacACore 10.0.2.1 CampusCore Switches VLAN2 Interface IP
FacBCore 10.0.2.1 CampusCore Switches VLAN2 Interface IP
Dept1PC none This is a L2 device
Dept2PC none This is a L2 device
Dept1PC 10.0.10.254 FacACore Switches VLAN10 Interface IP
Dept2PC 10.0.20.254 FacBCore Switches VLAN20 Interface IP
  • Now let's enable OSPF on Core devices. Starting from CampusCore
    • Login to CampusCore switch and switch to config mode
    • Define OSPF process and Process ID. In this lab use process ID as 1 
      CampusCore(config)#router ospf 1
    • Give the router ID 
      CampusCore(config-router)#router-id 10.0.2.1
    • You are going to announce the subnets which are directly connects to you. Use this command for that 
      CampusCore(config-router)#redistribute connected subnets
    • You are announcing to the core network (10.0.2.0/24) in area 2. Use this command for this 
      CampusCore(config-router)#network 10.0.2.0 0.0.0.255 area 2
CampusCore(config-router)#exit
    • You are enabling OSPF on VLAN 2. Use this command for that. 
      CampusCore(config)#interface vlan 2
CampusCore(config-if)# ip ospf 1 area 2
CampusCore(config-if)# exit
    • Now you have enable OSPF on CampusCore Switch. Now lets add the default Route. 
      CampusCore(config)# ip route 0.0.0.0 0.0.0.0 10.0.255.254
  • Follow the same steps in FacACore and FacBCore
    • FacACore 
      FacACore(config)#router ospf 1
FacACore(config-router)#router-id 10.0.2.2
FacACore(config-router)#redistribute connected subnets
FacACore(config-router)#network 10.0.2.0 0.0.0.255 area 2
FacACore(config-router)#exit
FacACore(config)#interface vlan 2
FacACore(config-if)# ip ospf 1 area 2
FacACore(config-if)# exit
FacACore(config)# ip route 0.0.0.0 0.0.0.0 10.0.2.1
    • FacBCore 
      FacBCore(config)#router ospf 1
FacBCore(config-router)#router-id 10.0.2.3
FacBCore(config-router)#redistribute connected subnets
FacBCore(config-router)#network 10.0.2.0 0.0.0.255 area 2
FacBCore(config-router)#exit
FacBCore(config)#interface vlan 2
FacBCore(config-if)# ip ospf 1 area 2
FacBCore(config-if)# exit
FacBCore(config)# ip route 0.0.0.0 0.0.0.0 10.0.2.1
  • Now you have enable Routing in your Core network. Let's verify whether it is working.
    • Go to Dept1PC and try a Ping to Dept2PC 
      ping 10.0.20.1
    • It should give you a reply
  • add the BorderRt Routers default gateway
    • Go to BorderRt and switch to config mode
    • Add the default route 
      BorderRt(config)# ip route 0.0.0.0 0.0.0.0 192.248.6.254
    • Verify the route by ping a known host from the BorderRt router 
      ping 192.248.1.161
ping www.google.com
    • Both should give you a reply
  • Some troubleshooting commands
    • You can get the routing table by following 
      Router#show ip route
    • To get OSPF routes 
      Router#show ip route ospf
    • To get ospf neighbors 
      Router#show ip ospf neighbor
    • To reset OSPF process 
      clear ip ospf process

Router Configuration

Now you have complete most of the IPv4 Configurations. Go to DeptPC1 and try a ping to the DNS server (192.248.1.161). You will not get a reply. That is because your PC have a private IP. There must be a method to connect to the outside using a private IP. What we use here is adding a NAT in BorderRt router. There are different NAT types what we use here is the method called NAT overload. In this method we can assign set of local(private) IP's and overload it to a interface with a global(public) IP. So the outside the network will see the traffic coming from local IP's as traffic coming from the global IP. Let's add this configuration to your router.

  • Login to BorderRt Router and switch to config mode
  • Let's define the local IP set in a ACL. 
    BorderRt(config)#access-list 1 permit 10.0.0.0 0.0.255.255
  • Then dd the NAT entry. In your router public IP is assign to FastEthernet 0/1 interface 
    BorderRt(config)#ip nat inside source list 1 interface FastEthernet0/1 overload
  • Then define NAT inside & NAT outside. NAT inside is your router's LAN port and Nat outside is your router's WAN port. 
    BorderRt(config)#interface FastEthernet 0/0
BorderRt(config-if)#ip nat inside
BorderRt(config-if)#exit
BorderRt(config)#interface FastEthernet 0/1
BorderRt(config-if)#ip nat outside
BorderRt(config-if)#exit
  • Finally add a static route in the router so that the traffic coming to our defined network will redirect to CampusCore switch 
    BorderRt(config)#ip route 10.0.0.0 255.255.0.0 10.0.255.253
  • Now try a ping from DeptPC1 to the DNS server. It should give reply
  • Use the following for NAT troubleshooting 
    Router#show ip nat translation

You have successfully complete the IPv4 configurations. save all the configurations in all the routers

Wireshark

Let's capture some packets and do a analysis.

  • Log in to Dept1PC and and start blackbox. 
    sudo startx
  • Right click on desktop and open xterm terminal
  • type wireshark and press enter
  • On the wireshark interface select the enp0s3 interface and click Capture packets button
  • While you are capturing. Open another xterm terminal. And type midori and press enter.
  • You will get midori browser. Click the arrow head at top right corner to get the menu. In the menu select New Private Browsing Window
  • Browse for www.google.com from the browser.
  • Go back to wireshark and stop capturing
  • You will see plenty of broadcast packets. They will look like following 
    NO	Time		Source			Destination	Protocol	Length	Info
9	0.579325000	00:fe:c9:3e:13:a0	Broadcast	ARP		60	Who has x.x.x.x?  Tell y.y.y.y
  • Click on Statistics and select Summary
  • You will get a summary window and it will show you some percentages. You will see a high percentage of ARP messages.
  • Go to file in main menu and click close and exit without saving
  • You will get the initial interface. Select enp0s3 interface
  • click on the green flag in the using this filter... dropdown list.
  • Select New capture filter:icmp6
  • Start Capturing

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